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HP-UX 11i Version 3: February 2007

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ctermid() — generate file name for terminal


#include <stdio.h>

char *ctermid(char *s);


ctermid() generates a string that, when used as a pathname, refers to the controlling terminal for the current process.

If s is a NULL pointer, the string is stored in an internal static area, the contents of which are overwritten at the next call to ctermid(), and the address of which is returned. Otherwise, s is assumed to point to a character array of at least L_ctermid elements; the path name is placed in this array and the value of s is returned. The constant L_ctermid is defined in the <stdio.h> header file.

If the process has no controlling terminal, the pathname for the controlling terminal cannot be determined, or some other error occurs, ctermid() returns an empty string.

For multi-thread applications, if s is a NULL pointer, the operation is not performed and a NULL pointer is returned.


The difference between ctermid() and ttyname() is that ttyname() must be handed a file descriptor and returns the actual name of the terminal associated with that file descriptor, while ctermid() returns a string (/dev/tty) that refers to the terminal if used as a file name. (see ttyname(3C)). Thus ttyname() is useful only if the process already has at least one file open to a terminal.


ctermid(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1

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